1. Field of the Invention
This invention relates to heat-resistant, corrosion-resistant inorganic composite bodies and a process for the preparation thereof and more particularly it relates to such inorganic composite bodies which may suitably be used as various articles under high-temperature and highly oxidizing conditions and are superior in various properties such as oxidation wear-resistance and heat-resistant strength, said various articles including pipes for blowing a gas therethrough into a molten metal, an article (such as a crucible for melting a metal therein) contacting with a molten metal, and electrodes for use in making electric furnace steal. The terms "oxidation-wear resistance" and "heat-resistant strength" are intended to mean "wear resistance under oxidizing conditions" and "strength under high temperature conditions" respectively.
2. Prior Art
Heat-resistant, corrosion-resistant inorganic composite bodies, such as an article contacting with a molten metal, which are used under high-temperature and highly oxidizing conditions, include heat-resistant inorganic compound bodies, such as artificial graphite bodies and C/C composites, which are composed mainly of carbon and/or graphite, and said bodies impregnated with a phosphoric acid compound such as phosphoric acid and salts thereof or coated with silicon dioxide (SiO.sub.2) or a metal oxide, such as alumina (Al.sub.2 O.sub.3), by plasma irradiation or the like.
However, the above-mentioned heat-resistant inorganic compound bodies composed mainly of carbon and/or graphite are not fully satisfactory in oxidation wear-resistance and heat-resistant strength and are difficult to use stably for a long period of time as an article contacting with a molten metal. Said heat-resistant inorganic compound bodies will be somewhat improved in oxidation wear-resistance by impregnating with a phosphoric acid compound or coating with a metal oxide, whereby heat-resistant and corrosion-resistant inorganic composite bodies having fully satisfactory properties cannot be obtained.